The irreversible inactivation of two copper-dependent monooxygenases by sulfite: peptidylglycine α-amidating enzyme and dopamine β-monooxygenase

David J. Merkler, Raviraj Kulathila, Wilson A. Francisco, David E. Ash, Joseph Bell

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15 Scopus citations


Peptidylglycine α-amidating enzyme (α-AE) and dopamine β-monooxygenase (DβM), two copper-dependent monooxygenases that have catalytic and structural similarities, are irreversibly inactivated by sodium sulfite in a time- and concentration-dependent manner. Studies with α-AE show that the sulfite-mediated inactivation is dependent on the presence of redox active transition metals free in solution, with Cu(II) being the most effective in supporting the inactivation reaction. Sulfite inactivation of α-AE is specific for the monooxygenase reaction of this bifunctional enzyme and amidated peptides provide protection against the inactivation. Consequently, the sulfite-mediated inactivation of α-AE and DβM most likely results from the transition metal-catalyzed oxidation of sulfite to the sulfite radical, SO3 -.

Original languageEnglish (US)
Pages (from-to)165-169
Number of pages5
JournalFEBS Letters
Issue number2-3
Publication statusPublished - Jun 12 1995
Externally publishedYes



  • Copper-dependent monooxygenase
  • Dopamine hydroxylation
  • Peptide α-amidation
  • Sulfite-mediated inactivation

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Cell Biology
  • Genetics
  • Molecular Biology
  • Structural Biology

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